Renowned British military surgeon James Barry was a pioneer in his field and enjoyed a celebrated and highly-accomplished career for over 50 years. After his death in 1865, it was discovered that he was actually a woman named Margaret Ann Bulkley. Source
This actually happened in Athens once. This lady went to Egypt to get her medical eduction and then came back home pretending to be a man and when the percentage of women surviving childbirth went up under her care the other doctors got jealous and accused her of sleeping with her patients, to which she replied by taking off all of her clothes and asking them if they still thought that and that was how Athens allowed women to be doctors
I could concentrate on nothing but him dimples. They were so endearing that I knew girls all over must fall for him, much like I did. But I am no girl. And he is not homosexual. It is not meant to be. Was not meant to be. I must move on. He is not... As you might say... Inclined to love me. - Hetty
"The devil!" cried Sophia as she pulled up his nightshirt to wash his body and, quite literally, uncovered a secret the doctor had managed to hide for most of his life. "It's a woman - and [noting what she took for stretch marks on his stomach] a woman that has had a child." This truth was so scandalous to Victorian Britain that for years it was hushed up. Dr James Barry was one of the most highly respected surgeons of his day.